1. Field of the Invention
The present invention relates to a novel and highly advantageous process of producing acylamino methane phosphonic acids and their salts, to compounds obtained by said process, to a method of using said compounds, and to compositions useful for such purpose.
2. Description of the Prior Art
U.S. Pat. Nos. 2,304,156; 2,328,358; and 2,862,882 describe processes of making acylamino methane phosphonic acids. According to said patents, N-methylol compounds of carboxylic acid amides are reacted with phosphorous trichloride. The reaction mixture is then hydrolyzed by the addition of acetic acid or hydrochloric acid. The starting methylol compounds are obtained as described in Ann. 343 (1905) 210 by reaction of amides with formaldehyde or by decomposition of the corresponding chloromethyl compounds according to U.S. Pat. No. 2,131,362.